Photocomposing apparatus



July 6, 1954 R, A. HlGoNNE-r ET A1. 2,682,814

PHOTOCOMPOSING APPARATUS Y Filed Jan. 12, 1949 66 e sheets-sheet 1 July 6, 1954 R. A. HIGONNET x-:T A1. 2,682,814

PHOTOCOMPOSING APPARATUS Filed Jan. l2, 1949 8 Sheets-Sheet 2 F; A A {NVENToRs 3 @u @.{MYQM /aw www n July 6, 1954 R. A. vl-ncomuET ET AL PHOTOCOMPOSING APPARATUS 8 Sheets-Sheet 3 I Filed Jan. 12, 1949 O -PLM' C)O AJuly 6 1954 R. A. HIGONNET ET AL 2,682,814

PHOTOCOMPOSING APPARATUS Filed Jan. 12, 1949 8 Sheets-Sheet 4 Inventors fwn/M WMA/WW @2.

July 6, 1954 R, A. HIGONNET ET AL 2,682,814

PHoTocoMPosING APPARATUS Filed Jan. 12, 1949 s Smets-sheet 5 July 6, 1954 R. A. HIGONNET Er A1. 2,682,814

PHOTocoMPosING APPARATUS l Filed Jan. 12, 1949 8 Sheets-Sheet l6 Inventors July 6, 1954 R. A. HIGONNET ET AL 2,682,814

PHoTocoMPosING APPARATUS Filed Jan. 12, l1949 r 8 Sheets-Sheet 7 Inventcrs widthvaiues.

July :6, 1954 R. A. HIGONNET ET AL 2,682,814

PHoTocoMPosING APPARATUS Filed Jan. l2, 1949 8 Sheetsheet 8 Q is IAQ QQ Q:

Inventors lfm d MW vir* v i Patented July 6, 1954 UNITED "STATES OFFICE "Pno'i-OCOMPOSING APPARATUS Ren.A. {Iigonnetand Louis Moyroud, Camli'dge, ;Mass., ',alssignors'to Graphic Arts Re- Search Foundation, Inc., Cambridge AMass., -a

corporation of Delaware @Application-:January 12, 1949,`seri.1'N0170,4'72

Claims priority, application Ira'nce January 14, -19`48 26 Claims.

"KIhe present 2irifv'erition "relates to "photo-'comps'ing `#apparatus 'and 'lis more particularly conffc'er'ne'd @with apparatus f -the general type def-s'clbeti in fouricopendi-ig applications- Serial I`Nos.

610,334, now Patent No. 2,486,406, of November l, 1949; 610,335, now abandoned;.610,336tii1ed August 11, .1945; 'ocbs'z, "nieu catchers, 1946, now abandoned; 'and 770,320, filed August 23, i194?.

FCneof the? principali-obj ects f of the present in- 4ventionris togprovide improvementsin the apparatus-a 'describediin--saidf' applicationsfwith particu- Ilar views-to :the `utilization sof `'certain standard 'fedui-pment, and fthe improvement #of fthe :speed accuracy and reliability of the system.

.mntherrobjeotiisvto provideanvimprovedmode :df ijustication. lat. :still @further-:object vis' to wim- -prove `and @simplify the :introduction of 'correc- .ftioiisfWith 1.these and xo'ther rpbjedts in view, @as `will v)hereinafter fappear, tlie #invention preferably fmakes"'usef offstandar-d :relaysfstepping `relays I:and the dike, which fare Well i'known in "the "telephone Land fsignaling arts `and fwhich A"have r been found capable lof :operating reliably A*for an extremely large numb ertnfcycles.

rfeature-Lof etheinvention comprises a justifyfing ;.procedu1e'-1'vvhich 4:may:rbeieX-ecuted more rapidly `and -with Iles's `:speciall equipment than that "described in the fabove applications "This `.proy:ceilure .is outlined `as llfolloivs: :Let 1-the desired .len'gthioffth'eline ber-represented as J infarbi .ftrary u1-nits) Upon actuation fof the typewriter keys to ra point wlreretthe total fwidths :of Achar- .1ac't"ers""` (plus .fm-inimalintervvordiiwidths) Vfall'slirt lof :.I'fbysso'me deflcitD, .the interwords'spacesfare to be increased by distributing L'D units-among .the iinter-Words, Iunder fthe condition, f'how'e'ver, that feach -intervvo'rfd to ibe-fch'anged only 'by I"a vdiscret'e ninbe'rfof luriits. lffhe requirement for changingiinterwordsbyldiscreteunits isf'or proper actuation 'of the fhn carriage, described in said prior applications?) y"If N fis the number 'of "intervvo'rds, "the .ratio D/NWill not in general `be an integer. Accdrdingto our application Ser.` No. 1`6l0,`33`6, the allocation of theD units to the iN interwor'dsfis-accomplished by adding a certain number Qorurits lto-.eachfinterwordfo'f one zgroup` and Q-i-l units -Yto .eachinterwordnfa second ggroup. --According to :present invention 'the )same :mathematical A:princi-ples 'fare ffollowed, .but

ian improved apparatusis'used. The apparatus includes va f'eounter :tlinto which @the @number .fof

iinterwords .Eis succe'ssifvely added to the funjsti- 1 fied flire :length Thus, the 4counter successively carries :the totals YJ-'D (unjustified line) J .D-i-N `(first addition) J D4-ZN l(second addition) fetc. This ,procedure 'is repeated 'until the Vvalue J Vis edualled or exceeded, whereupon the system is actuated,fas Will be described later i'n detail, "to effect the proper allocation of width-units to the interwords.

`A feature of the invention resides in the use 'of thebinary number system for the computations. `As is Well known, V'the binary system has -bii't'two digits, v0.and 1, whereby successive inteigersare .represented as 0, 1, 10, 11, 100, etc. (cor-- vresponding,respectively toO, 1, 2, 3, 4, etc. in the decimal system)` The binary system is prefer- .able 'for a number of reasons; first because any relay .or switch is required to have only ytwo positions, as an attracted or-retracted position of an armature, or aclosed or open circuit, representying a".yes or no, or a G or 1'condition only. AAnother advantage is in the fact that subtractions can be more readily made than in other systems. vSubtractions are used in correcting-and can-be effected in .the'binary'system by -a relatively simple process of inversion.

Other features ofthe invention consist of certain novel features of Vconstruction and combinations and arrangements otparts hereinafter described `and particularly defined in the claims.

y In .the accompanying drawingsfFig. 1 is -a'block diagram of the preferred embodiment of the present invention; Figs. 2 and 3 are diagrams of flipflop circuits; Figs. 4 and 5 are diagrams of countingcircuits; Fig. V6 is a diagram of the keyboard Vand .associated equipment; Fig. 7 is a diagram of the line contour and associated equipment; Fig. 8 is a diagram of the interWord counter, zone switch, remainder switch 1and associated equipment; Fig. 9 is a diagram of the width translator and associated relays; lFig. 10 is a diagram of fthe meter control; and Fig. 11 is a'diagram of the V4flasher and variable .'escapement circuits.

Block Lvdiagram The invention 'will f'be described kvin connection lwithfthe'blockdiagram of Fig.1. The apparatus indicated in the block I-D at thelowe'rfleft hand `vc`oi'`iie'r o'flFig. 1,fc'om'p`rises' the typewriter' 'ha-ving rafk`eylo'oa1"d,'the permutation bars actuated by the "typewriter keys andthe register 'fo'r storing the "coded information corresponding to Ythe selecftion o'f ia given character. Asexplained in our copending application, Ser. No. 770,320, the system preferably includes a register having two sets of pins whereby the coded information already stored on one set of pins may be coded and transmitted to the flash unit and variable escapement while a subsequent line is being typed on the typewriter. In common with usual printing techniques various characters of the font are allocated arbitrary width-values. For example, in a representative font, the width values of i and 1 are 5 units; f and j, 6; a, g and numerals, 9; b, h, n and s, T, F and L, 12; M, H and W, 15. An arbitrary minimum interword value is also assigned which, by way of example will be taken as 4 units.

On each actuation of any character of the typewriter, the register is operated to store the required information. Also on each actuation of a character the width value thereof is transmitted to the line counter I2. For this purpose four leads I4 connect the block I0 with the block I2 in Fig. l. It will be noted from the above that twelve different width values, ranging from the interword value (4 units) to W (l5 units) are generally sufficient to cover all possible fonts. For this it suices to have four leads I4 (because 24:16), although if a greater number of width values are required, a larger number of leads may be used.

Each actuation of the space bar, in addition to adding 4 units to the line counter, adds one into the interword counter CI, whereby the line counter accumulates the number of width units from the beginning' of the line and the interword counter accumulates the number of interwords. For this latter purpose, a connection I8 runs from a switch operated by the space bar of the typewriter to the interword counter CI.

In addition to the leads Id connecting the permutation bars with the line counter, there is a lead 2li operated by a universal switch for purposes to be described later.

At the completion of the typing of a line, the line is read by the operator and if it appears correct the operator presses a manual start key 22, which initiates operation of the justifying mechanism and thereafter automatically starts the printing cycle. The justifying operation will now be briefly described.

Let J represent the desired length of the line in the arbitray units and let L be the total width of all of the characters and minimum interwords, as stored on the register. The line is too short by the deficit D so that J -L=D. The object of justification is to distribute among the interwords the deficit D so that the length of the line will be increased from L to exactly J.

Let N be the number of interwords; then the relation between the deficit D and the number N may be expressed as follows:

where Q is the integral value of the quotient of N into D, and R is the remainder. If we were to add to each interword the quantity Q-I-R/N, it would necessitate the use of a film carriage capable of being displaced by any fractional amount of one length unit. Such devices have the disadvantages that they are delicate in adjustment and that the errors accumulate from one interword to the others. On the contrary in variable escapement devices which move only by discrete number of units, errors do not accumulate. In order to take advantage of this type offvariable advance inechanismfor the film carriage the justifier adds Q units to the first N-R interwords, and Q-I-l units to the last R interwords. The number of length units thus added is The operation of the justifier will be described in conjunction with a numerical example. Let us suppose that D equals 4l, (that is, the line is 41 units too short) and that the number of interwords N equals l2.

Into the line counter I2 we now introduce the number N successively. This is done through the live leads 23 connecting the interword counter I6 with the line counter I2. In the example chosen the deficit D is therefore successively reduced from 41 to 29, to 17, and to 5. At the fourth addition the capacity of the counter is exceeded (and in the example chosen it is exceeded by exactly 7 units). The number of times that N has been added into the counter to tip the counter over is then exactly Q-I-l. The amount by which the capacity is exceeded is N-R. We now write the general Equation 2 again, and under it we write the numerical lvalues for this example as follows:

There is provided a remainder switch PR which is connected to the line counter I2 by a set-of five leads 24. The counter, as heretofore noted, displays at this time the number 7 (or in general, N-R) This value of N '-R is transmitted over the leads 24 to be recorded in the remainder switch PR.

There is also provided a zone switch SZ connected with the interword counter by a lead 25. This zone switch is first caused to store the number Q which is to be applied to the first NR interwords; for this example the zone switch is set at the value 3 which is to be applied to the first 7 interwords. A lead 26 connects the remainder switch PR with the zone switch SZ and acts to send into SZ an impulse on exhaustion of the value of N-R from'the remainder switch PR. In other words, as the escapement of the film carriage operates, the remainder switch PR. is caused to move one step nearer its home position for each interword. Upon arrival at its home position, which means that the first N-R interwords have been increased by Q, the impulse from PR changes the zone switch from Q to Q-H, whereby the remaining R interwords are increased by Q-I-l. (In the example chosen, PR takes 7 steps to its home position, and then changes the zone switch from 3 to 4 units for the remaining 5 interwords.)

Referring again to the block diagram, there is provided a block indicated at 28 and designated width translator, signal translator and repeater. This block 28 is connected to the block Il) by two sets of leads, designated as a set of four width-selector leads 30 and a set of three character-selector leads 32. These leads are energized by the reading mechanism of the register. The four leads 30 serve to select the width of the vcharacter and to initiate correct operation of the variable escapement mechanism. The three leads 32 select the required characters from all characters, having the same width. For example, b and h have the same width so that the leads 30 carry the same impulses therefor. However the leads 32 carry different impulses for these two characters. If not more than eight characters have the same width, three leads 32 are sufficient.

Actually in most fonts there are more than eight characters for some -of the widths. This may be taken care of by additional leads 32, but as will be shown later, such additional leads are not necessary since the leads 30 are not lled to capacity for width selection, and empty values thereof may be used for character selection. From the width-translator 28 a cable of twelve leads 34 runs to the variable escapement mechanism 36. This is the variable escapement for the film carriage, which may be of the type described in our application Ser. No. 610,336 or 770,320. The impulses in leads 3-0 and 32 are transmitted through a signal translator and repeater through seven leads 3S into the flasher unit 40y by which theselected character is illuminated at the proper time to throw its image on the photographic sheet as described in our copenging applications, Ser. No. 610,335 and 610,336,

The zone switch SZ is connected through seventeen leads 42 with the block 36. Whenever an interword is called for by the'leads 30 and 32, the flasher is not operated but a signal is sent from the signal translator to the zone switch SZ over` a lead 43. The width of the interword is determined by the setting of the zone switch, whereby a signal is transmitted into the variable escapement mechanism through one of the leads 42. `The minimum interword width is 4 units, and since the maximum found necessary is 18, the leads 42 are more than are needed for ordinary justification. However, since interwords of 1, 2 and 3 units are not used, these values are reserved for justiiication between the characters of a word, as will be explained later. In the example chosen the zone switch will signal the Variable escapernent mechanism for an increment of 3 units for the first seven interwords and an increment of 4 units for the last ve interwords, whereby the actual spaces will be 7 units for the first seven interwords and 8 units for the last ve interwords.

So far the mathematical principles on which the justification is based have been described as if the computations were carried out in the decimal system. The actual computations are, however, preferably carried out in the binary system. The structure of the various units and the mode of computation in the binary system will presently be described in detail. However, since one of the important units in the system is a special counter, the principles of operation of the counter will rst be explained, after which the actual components of the system will be described in detail.

Line counter It has been explained in the copending application Ser. No. 610,336, how the key bars of the typewriter operate a set of permutation bars and close their associated contacts according to the code combination allocated to the vari-v ous characters. We shall only consider here the rst four contacts which characterize the character widths. The corresponding four contacts are connected to the four entries of the binary counter. It is clear that these four entries must 'be adapted to operate simultaneously since the permutation bar contacts are simultaneously operated. The result of the addition of these various numbers in the counter is recorded in binary or accumulating relays, or combinations of relays. These relays'are such that they have two stable positions, and they move from one position to the other when current is applied and interrupted, and then remain inv this latter position. For this reason they may be called flip-iiops. Figure 2 shows an embodiment using a stepping relay or switch commonly used in telephony. This relay comprises a pawl 44 and ratchet 46. When the current is applied to the magnet 48 the armature 5i] pulls the pawl backwards against a spring 52 and when the current is cut off the pawl advances the contact disk 54 one step. One b-rush 56 engages the disk near itscenter and the other brush 58 either engages the metal portion to close the circuit or lies on an insulating portion to open the circuit. Thus the circuit is closed following every second energization of the magnet 48. An auxiliary magnet BG is also supplied for a purpose to be described later.

Figure 3 represents a so-called flip-flop circuit which gives the same results but which uses ordinary telephone relays instead of the more expensive rotary switches. In Fig. 3 when the ground is applied through switch S, current flows through relay B2 and one winding of relay 64 in series, but the single winding of 64 is too weak to operate 64. (The term operate is used herein to refer to an attraction of the armature.) Hence relay 62 alone operates. When the switch is opened the second winding ofV E4, which during the impulse was connected to ground on both sides is now excited, and both windings of 64 and the winding of relay 62 remain energized. Both armatures are attracted. When the switch closes a second time relay 52 has both terminals connected to ground and releases, but 64 remains operated by its half winding.y (This is a well-known type of double-Winding relay in which one winding is unable to operate the relay but is able to maintain it in the operated condition.) When the switch is opened 4 releases and the cycle can repeat. Contacts G5 controlled by relay 64 are adapted for connection in an external circuit. These contacts close for every two actuations of switch S and hence function in the same manner as 56, 53 of Fig. 2.

If we consider now the binary relay of a given stage it is clear that it must operate when one impulse is applied to it, and that it must carry over this same impulse to the higher order if it is already in its operated or one position, and that it must not transmit a carry impulse if it is in its zero position. However, if a stage receives both a carry-over impulse from the lower order and a direct impulse it must not operate, but must carry over a single impulse to the next higher order, whatever its own initial position may be.

Figure 4 is an example of an embodiment of a binary counter which fulfils these requirements. It comprises as many flip-liep relay circuits as there are stages. The iiip-flop circuits are shown at XI, X2 and X3 and may be of the form enclosed within the dotted lines of Fig. 2 or Fig. 3. Each iiip-iiop circuit is provided with contacts which are closed when the flip-flop circuit is in position l and open when it is in position 0. The contacts are shown at G6. Such simple make contacts on the flip-nop circuits would vbe suflicient if the entries on the various stages were not simultaneous, but occurred in succession.

When a nip-flop circuit receives a carry over potential from the preceding stage and an operating potential from its own stage it is not convenient to operate this flip-flop circuit twice. A more rapid and convenient arrangement is Such that a flip-flop circuit of a stage in which a double entry occurs is prevented from operating at al1, but it sends the next higher stage a carryover potential. The circuit shown in Fig. 4 fulfills these conditions. All stages are identical except the first one which, of course, cannot receive any carry-over potential. Each stage is provided with a carry over relay R2, R3, etc. These relays have two windings in 4opposition relation and operate whenever one winding is energized and remain at rest when both windings are energized. The input to the first stage is through a lead 61 having contacts (shown as a key Kl), said lead being connected direct to Xl and also to one of the contacts 66. A carry-over lead 68 runs from contacts 66 of Xl to one winding of R2. The input lead 69 of the second stage runs through K2 to the second winding of R2 and also through a rectifier 10 and lead 1I to contact 66 (but not to the flip-flop circuit X2 itself). A second rectifier 12 is connected between leads 68 and 1I.

The relay R2 has make contacts 13 connected by a lead 14 with X2, and break contacts 15 connected with the input lead 69 of its own stage and with a carry-over lead 16 running from con tacts 66 of X2 to one winding of R3.

The third and subsequent stages are simply a repetition of the second stage.

It will be observed that the counter of Fig. 4 has the advantage that a carry-over impulse is transmitted through all necessary stages without requiring successive operations of the relays. For example, if the three X-relays are all in their l-positions (corresponding to lll in the binary system or '1 in the decimal system), closure of KI sends a carry-over impulse directly through 66 of XI, rectifier 12, lead 1I, contacts 66 and lead 16 of the second stage, and through exactly similar connections of the third stage, direct to the fourth stage. Also the flip-flop relays of the first three stages convert to the condition in unison. The relay E is not operated to allow the flp-fiops to operate until after the carryover relays have assumed their correct positions. The ultimate result in this example is to 'record 1000, the sum of 111 and l in the binary system.

As a practical measure which will be explained later, relay E is introduced with contacts in the ground leads of the X relays. At this time it will be assumed that relay E is energized and its contacts are hence closed.

Let us consider the second stage, for instance. When a single entry is made, either from stage I through the closed contact (position 1) of fiipflop circuit XI or by a control potential applied by key K2, relay R2 operates since one of its windings only is energized. By its 'make contact vit operates flip-flop circuit X2. If flip-nop circuit X2 is on position 1 this operating potential is also transferred to relay R3 of the following stage and so on.

If, on the contrary, there are two simultaneous entries, one carry-over from the rst stage through KI and the contact 66 of fiip-flop circuit Xl (in its closed or "1 position) and key K2 of the second stage relay R2 does not operate since both its windings are energized and the operating potential is transferred by the break contact of relay R2 at rest to relay R3 of the following stage.

Fig. shows another embodiment in which the permutation bars actuate input relays CI, C2,

C3, C4, C5. In this form the carry-over relay R2 has only a single winding. All other carryover relays have two windings, either or both of which will operate the relay. The connections are not described in detail but the operation is clear from the drawing. Let us take as an example, XI on position 1 and relays CI and C2 operated by the permutation bars. Switch XI is excited by Cl, relay R2 operates, and the potential given by the make contact of R2 is not applied to the binary relay X2 but transfers a carry-over signal by the transfer contact of C2 and energizes relay R3 which operates by its first winding. By the transfer contact of C2 and the break contact of the transfer contacts of C3 at rest X3 is excited. Rectifiers are provided to prevent the unwanted operation of carry-over relays of lower orders. It is thus seen that carryover relays can be operated by two methods; either when' the preceding switch contact transmits a carry-over potential, or when the preceding carry-over relay is operated and a. simultaneous entry is made. I'he relay E in Fig. 5 serves the same purpose as its counterpart in Fig. 4.

When it is desired to make a subtraction, as for example in the case of an error, it is sufficient to reverse the position of all the flip-flop circuits, add the number to be subtracted and reverse again the position of all the flip-flops. This is readily done with stepping switches, since it is only necessary to energize the auxiliary winding 60 of each relay (Fig. 2) for this purpose. By exciting all these auxiliary windings simultaneously the positions of all the switches are reversed. The subtraction procedure for telephone relays will be described later.

Justifier computation The operation of the justifier mechanism will be described in relation to the detailed diagram shown in Figs. 6 to 11. The typewriter is shown in the lower left hand corner of Fig. 6. When the operator depresses one key he operates a number of the permutation bars (as described in our copending application Ser. No. 610,336) and closes the corresponding associated contacts cdl, cd2, cd3, cdd, which characterize the character width and contacts cd5, cdl and cd1 which differentiate the characters of same width and do not enter into the justification process. Since the permutation bar contacts may be closed for slightly different lengths of time intermediate relays RI-I, RI2, R12-3 and RI-4 are introduced between the permutation bar contacts and the counter. These relays are operated through leads I4 by the permutation bar contacts cd and lock themselves by holding circuits established through their make-before-break contacts and a now-closed break contact of a special delay relay DR. In this way it is possible to maintain these relays operated for an appropriate length of time whatever the duration of closure of the permutation bar contacts. The intermediate relays, when operated, apply a battery to the counter input leads through a switching relay CS at rest. The counter (Fig. 7) comprises five stages with five carry-over relays R2 to R6 and five binary relay combinations AI--Bl toV A5-B5 of the type described in Fig. 3. The entire counter of Fig. '7 is identical with that of Fig. 4, the Al-BI, A2B2 relay combinations being the same as XI, X2, etc. of Fig. 4. Four stages are sufficient to take care of the character widths but it is desirable to provide an additional counter stage lin order to take care of more than I interwords, since as previously noted, the number N of interwords is fed into the line counter through the leads 23. Whenever any key of the typewriter keyboard CL is depressed a contact u, called universal contact, is operated. This contact operates a relay RU which also locks itself on the break contact of relay DR.. Another relay E is operated by make contacts of relays RI-I to RI-ll and RU in parallel. The object rof this relay E is to delay the application of the battery to the binary relays and thus give to the carryover relaysRZ to R6 the time to operate and prepare the circuit.

When the live-stage binary counter reaches its capacity an impulse is sent to the stepping switch ACS (accumulating switch) which advances one step. Switch ACS is a stepping switch (Fig. 6) which advances one step for each 32 units counted on the binary counter. It may be viewed as a scale-of-32 counter which has a capacity suilicient to store the total number of units in the line. The impulse is transmitted as follows: When the binary counter exceeds its capacity a circuit is completed through the carry-over relay RB in the same way that carry-overs are effected at any stage of the counter itself, as explained in connection with Fig. 4. When R6 closes its contacts it transmits a pulse over a lead 80, a contact of switch COS to be later described and a lead 82 to ACS. Energization of the winding followed by deenergization after R6 opens causes a `one-step advance of the contacts of ACS.

It has been noted that the relay RU is used to provide for the condition in which there are more than eight characters for a given width value, e. g., in a representative font there are twenty characters of 9 units width and fourteen of 10 units. Since widths of 0, 1, 2, and 3 are not needed in a normal font (the narrowest character being the minimum interword of 4 units), these empty values may be used to -increase the number available for character selection for certain widths. This is most conveniently taken care of by the circuit shown in Fig. v'7. The relay RUiwhich operated for every character is effective whenever binary values 0, 1, IO-and l1 appear on therelays RI-I. and'RI-Z, in Vother words, whenever -RI-3 and RI-,d are not operated. I A connection runs from a battery through a malte contact of RU, break contacts of RI-4 ,and RI-3, a transfer contact of RI-Z to the Vjunction of'two rectifiers rds 'and rtl4 respectively connected to counter input leads having `values ,of 1 and 8 (binary-1000). Thus, `when no RI relay isoperated, a signal of value'9fis` sent through the two rectifiers` into the countcr;` when only RI`| is operated, the same value is sent into the counter, the rectiiie: T113 being shunted by the make contacts of RI-l; when RI1-2 alone isoperated,r its value of 2 is increased toten by the operated transfer contact connected to the fourth input lead; finally, it follows from the foregoing that when RI-l and RI-Z are both operated a width value of eleven units is sent to the counter.

Stepping switch nomenclature For certain of the stepping switches, notably ACS andSZ, the actual step contacts are shown. For others, however, a. simplified drawing is used, and the contacts are designated by a standard convention. The various levels of the switches are designated by capital letters without subscripts, A, B, C, etc. Thus the correction switch COS (Fig. 6) has seven levels designated A to G.

, 10 The contacts of the various levels are designated A 1/4 B 3 C 0 D 4 E 3 F 2.4 G 2/3 Each number represents a closed contact. The mark means that vall contacts between the two numbers are closed, while the dot means that all contacts between the two numbers are open. Thus level A is open on its home position 0 but is closed on all steps from 1 through 4. Level B is closed on step 3 only, C on position 0 only, D on 4, E on 3, F on 2 and 4 (but open'on step 3) and G on 2 and 3. This convention will be used throughout.

Correction procedure Before proceeding with the description of the intel-word counter and associated equipment, the procedure of making `a correction will be eX- plained. If the operator sees that he has made an error, it is necessary to erase the wrong character from the register and also to subtract its width Value from the line counter, before introducing the correct character. The operator merely resets the typewriter platen back to the wrong character and then presses the correction key COK. This energizes the stepping switch designated COS (correction switch). The subtraction is eifected by inverting the binary counter (i. e. changing all ls to 0, and all Os to l), adding the number to be subtracted, and then reinverting the binary counter. This is the mathematical process of subtracting by adding complements; for example to subtract 11 from 1000 in the binary system, invert 1000 to obtain 0111, add 11 to obtain 1010, and reinvert to obtain the result 0101. This latter procedure is carried out by COS, which, when COK falls back, is connected by its level A to an impulse generator G comprising a cam Ca2 (Fig. 11) driven by the shaft of the printing unit similar to that described in our copending application Ser. No. 770,320. Switch'COS moves therefore 4 steps until it reaches its fth position which is also its starting position and in which its connection with the impulse source is interrupted. During its rotation this switch controls the following operations: first it disconnects the winding of ACS from the make contact of R6 by its level C-0 (note that the C level provides a closed contact only on position 0) On step 2 by its level F switch COS sends an impulse over lead 84 to relay INV (inversion relay). The inversion relay closes its contacts and sends an impulse over each of leads |20 toall of the relays AI to A5 and BI to B5 of the binarycounter. From the description of the counter previously given, it will be seen that this will invert each binary stage, that is, it will change a 0 position, wherever it exists to a "1 position, and will change a 1, wherever it exists, to a 0.

On step 3 level B of COS connects the SUS stepping switch (subtraction switch) to the make contact of relay R6 by leads 80 and 85. In Vother words it has disconnected ACS from this carryover relay R and has connected SUS in its place for a reason to be explained below. On both steps 2 and 3 COS operates by its level G and wireA 36 a sensing magnet COC which detects the position of the first four pins of the register to determine the width of the faulty character. In

1 l position 3 by its level E COS sends an impulse through lead 3l to the contacts of the COC magnet which are closed by the register pins corresponding to the erroneous character. The cone tacts of the COC magnet are in parallel with contacts cdl to edt of the keyboard. Hence leads I4 carry to the intermediate relays RII-l to RI-ll and RU the same values that were transmitted when the erroneous character was set up. The impulse to relay RU is actually provided by means of an auxiliary make contact on COC and wire 88.

If a carry-over occurs at this stage of the correction process it must be subtracted from the accumulating switch ACS since, if a carry over occurs in the subtraction of an erroneous width, it is necessarily because a carry-over also occurred when the erroneous character was typed. To come back to the correct position it would be necessary to step ACS one step back. Since the usual stepping switches are not adapted to move backwards the auxiliary stepping switch SUS has been provided. This stepping switch receives any carry-over which may occur during the subtraction process and moves one step backwards the end of line terminal of ACS. In Fig. 7 it may be seen that ACS gives a signal that the capacity of the counter has been reached, or exceeded, when its brush bl reaches terminal f. But if SUS has moved one step it may be seen that ACS Will have to move one more step than normally. In position 4 COS by its level F sends another impulse to relay INV which reverses again the position of all the binary relays. The Width of the erroneous character has thus been subtracted from the counter. In position 4 by its level D COS energizes electromagnet EF which pushes back into their set position the register pins of the faulty character. At the end of the fourth impulse switch COS falls into its fth position (which is also its zero position) where it is disconnected from the impulse source. The correction cycle is now completed and the operator can strike the correct character.

I 'nterword counter While the length of the line is being recorded in binary numbers in the counter, the interword counter CI records the number of interwords. This counter CI is also a switch of the stepping type and receives an impulse each time the space bar is depressed by the operator. It is provided with ve levels A to E which translate the number of interwords into a binary number for use in the justification process and has a capacity of 25, suflicient in practice. In accordance with the convention described above the levels of CI are described as follows:

B 2/3/'1.1o/11.14/15-18/19-22/23 c 4/7.12/15.2o/23 D amaze/24 The operation of the justier will be described in terms of a numerical example. Let us suppose that the line is 41 units too short, or that in other words the line decit is equal to 41, and that there are 13 words and consequently 12 nterwords. In this case the binary relays of the line counter are all in their operated, or l, position except relay Ali-B4 (8 units missing) and the accumulating switch ACS is one step (32 units missing) from its end position f. 40

impulses are necessary to bring all the line coun# ter relays to their operated (1) positions and to put ACS on its terminal f, and one more impulse to send a carry-over signal which denotes that the capacity of the counter has been exceeded; i. e. a total of 41 impulses. If D/N is not integral the counter will then display N'R.

The number of interwords N has been registered by stepping switch CI which has moved 12 steps under the control of the space bar of the typewriter, This switch is therefore on position 12.

The levels A to E of the interword counter stepping switch CI may be viewed as a converter to convert the number of steps into the binary code. Thus a closed contact on level A represents l; on level B, 2; on C, 4; on D, 8; on E, 16. Thus, on step 9, the contacts of levels A and C are closed; on step 19, the contacts of levels A. B and E are closed. In the example chosen it is seen that on step 12 the contacts of levels C and D are closed, corresponding respectively to 4 and 8, i. e. 12 in the decimal system.

Setting of justification apparatus The succession of operations involved in the justification is controlled by a master sequence stepping switch FLK. Switch FLK has the yfollowing designation of contacts for its diierent levels:

NCMDKU'IOONNCHH When the operator depresses the start key 22 the winding of the switch FLK is excited and when the key is released the switch steps into position 1 where, by its level A its winding is connected by lead 9-0 to the source 0f electrical impulses G, at the rate of l0 per second for instance. FLK moves immediately to position 2 where it stops. In this position it operates the switching relay CS which connects the counter to the five levels of CI and by its level C FLK sends an impulse to the common point 94 of the five binary levels of the interword counter CI. As explained above this adds 12 to the line counter for each impulse. The decit D is therefore successively reduced from 41 to 29, to 17, and to 5. At the fourth impulse the capacity of the line counter is exceeded, and the carry-over relay R6 is operated in the same manner as previously described. An impulse is then transmitted through leads and |00 to level D which at this time is on terminal f, which represents the normal end of the line. (Note that if a correction has been made which required stepping of SUS, the end of the line will be represented by a contact to the right of terminal f.) The impulse continues through a contact on level D of SUS, lead |02, level D of FLK to the winding of FLK. At the end of the impulse FLK steps to position 3 and by opening the contacts of level C stops the sending of impulses into the line counter through CI. At this moment the line counter has tipped over and now displays the diierence between 12 and 5, i. e. 7. While FLK was in position 2 a switch SZ (zone 13 switch) had its winding connected to the common point S4 of levels A, B, C,D, E of CI by wire25 and level C of FLK. Switch SZy has therefore moved Q-l-l steps, and in the example chosen is now on position 4. v

In position 3.0i ELK two operations take place. First CI 'is sent back to its home position, since it is no longer needed, by means of the home return level Z of switch CI which is closed for all positions of CI except position 0, self-cycling contact rz of CI, wire |04, and level E on FLK in the well known self-cycling manner. Second the remainder switch PR assumes its operating position under the control of the counter. It has been explained how the counter has registered N-R, equal to 7 in the numerical example described. This means that binary relays A|, A2, and A3 are in their operated or l position. These relays, by their break contactsy complete a self-cycling circuit for the remainder switch PR. Switch PR is a stepping switch defined as follows: f

A 2.4.6.8....24 (all even numbers) B 2/3.6/7.l0/11.l4/l5.l8/l9.22/23 C 2/5.l0/13.18/2l Z 1/24 (home return) The self-cycling circuit for PR runs from the battery through level E of FLK (in position 3) a lead |06, a normally closed contact of a relay NJ (to be described later) a lead |08 to the common point of levels A-E of PR, and then by leads 24 to the ip-flop relays of the line counter. It may be seen that the self-cycling circuit of PR is thus closed until PR reaches position 18 (for the example chosen) where it stops, that is to say, it stops 7 steps from its end position 25. During these two operations the winding of FLK has been kept energized through the rectiiiers |0 and ||2. When both CI and PR have reached their positions as described above the battery is disconnected from FLK, which then moves into position 4 where its level B connects it again to the impulse source G,-so that it steps immediately Ato position 6 which is its home position. In

position 4 of FLK the binary relays whose battery lead goes through level J of FLK have been deenergized and in position 4 FLK operates relay JR (justification setting) from level G through lead H4. The purpose of` this will be described presently. X

VIn position 5 of FLK an impulse is also sent by level H by a lead H t0 the electromagnet EM of the typewriter which controls the escapement of the platen so as to place it opposite the rst row of register pins and thus in position to type the next line. It must be remembered that it is necessary to locate the platen of the typewriter so that the hammers are out of engagement with the register pins in order that it be possible to shift from one half of the register to the other half by sliding vertically the field of pins.

The justification computation is now completed and we are ready to start photo-composition.

Justification setting The justification relay JR (Fig. '7) has been mentioned. This relay has five sets of contacts I |8 in series with ve manually operated keys JKI. The contacts ||8 are connected to the inputs of the flip-flop circuits of the line counter 14 by leads |20. If none of the keys JKI are closed the counter remains empty. If any of the keys are closed, corresponding values are initially set into the line counter when FLK sends the impulse in position Ll. This cuts down the available capacity of the counter by the values initially set in. For example, ifA the total capacity of the line counting apparatus (|2 and ACS) is, say, 512, and it is desired to write a line of 504 units, 8 units will be set into the binary counter at the beginning of each line, if the fourth key JK is kept closed. If the line is to be reduced more than 31 units below capacity, the starting position of ACS is changed by sliding a bar JKZ (Fig. 6) which closes all but one contact d of the homereturn level of ACS.

Photo-composition Y When the register is shifted from one position to the other, a starting contact bs (Fig. 6) is temporarily opened and relay RS' (Fig. 9), which was unenergized because both ends of its winding were connected to the battery, operates and locks itself through resistance rb. Relay RS prepares the operating circuit of the carriage relay CR which operates when the starting cam Cal closes its contacts at an appropriate moment of the cycle. Relay CR operates and locks itself on the same resistance rb as relay' RS. Relay SE, which controls Vthe operation of the sensing carriage EXP of the register, also operates from the same source as CR, Vbut locks itself on level B of a stepping switch FLR (Fig. 8) for which the contact conventions are shown in the'drawing. This switch controls various auxiliary operations such as the feeding of vthe photographic film. Relay CR completes the operating circuit of the lm carriage variable escapement which comprises a main motor magnet EV and 18 solenoids which control the amount of escapement and therefore the advance of the film carriage. Simultaneously CR applies a battery to a lead IIS through a normally closed contact of a relay KL to be described later. The lead runs to contact 'w of the width-'selecting circuit comprising relays T| to T1 (Fig..9) Contact w is the first of a set oftransfer contacts, indicated as fanningout contacts |2| of the T-relays. These relays are operated through leads 30 and 32 by the sensing springs of theregister Cl and C1 shown in diagrammatic form on the left hand side of Fig. 6. When relay SE operates it closes the circuit of the magnet EXP which controls the escapement of the sensing carriage through lead |22 and cam Ca8. SE also closes the circuit of electromagnet PLP through lead |24 and cam Ca9. PLP operates the sensing springs and closes the contacts of those which meet the pins of the register which have been pushed in during the typing of the line by the operator. The corresponding relays T are operated and lock themselves through a holding circuit including cam Call), a lead |26 and contacts of relay CR. These relays T have a multiple purpose; rst they select the character to be photographed by their break contacts |28 which control the decoder |30 and flash circuit 40 through leads 30; and second, by their transfer contacts |2| they select the stop pins of the variable escapement through leads 34 fand thus control the displacement of the nlm carriage according to the widths allocated to the various characters. When for example the register has pins 3 and 4 in their pushed-in positions, relays TI, T3 and T4 are operated and the wire selected is that of stop l5 pin I3 since the binary value of pin combination |-3-4 is 1|4|-8, i. e. 13. Third, relays T translate coded signals, such as justifiable interwords, end of line signal, justication between characters and change of fonts.

When the sensing springs find in the register the pin combination 3, relay T3 alone is operated and the potential is directed through lead 43 to the brush of switch SZ, which is, for the example previously chosen, on position 4. The terminals of switch SZ are connected to the stop pins of the variable Vescapement as follows: terminal I to stop pin 4, terminal 2 to stop pin 5, terminal 3 to stop pin 6, terminal 4 to stop pin 'l and so on. In the present example SZ being on position 4 selects stop pin 'I and the variable escapement advances 7 units for each interword. Simultaneously, however, PR also moves one step for every interword signal, since it also is connected to lead 43. A lead |30 connected to 43 runs through level F of PR and a break contact of NJ to lead 25. When PR reaches its position 24 it sends by its level F an impulse'over lead |30 to SZ which then moves one step. Since PR was at 7 steps (in general, N-R steps) from position 24, the nrst 7 interwords will have a value of 7 units. Thereafter, the remaining R interwords will have a value of 8 units. This makes a total of 7 spaces with 7 units or 49 units, and 5 spaces with 8 units, or 40 units for a total of 89 units. However, since the counter has registered 4 units for every interword typed, the line has been increased only by 89 minus 48, or 41 units. Since this was the value of the decit in our example, the line is justiiied.

At the end of the line the register sensing springs nd the combination 3--5 which the operator has registered when throwing key 22. Relays T3 and T5 are operated and direct the control battery to the common point of resistance rb and relay RS. Relays RS and CR now have both ends of their windings connected to the battery and hence release. Relay SE however is kept operated for a short time by level B of FLR, since it is necessary to move the sensing carriage a few more steps for'restoring the last pins of register into their inactive positions. When CR releases it applies a battery by one of its break contacts to the clutch DEB which normally connects the variable escapement `EV to the film carriage. The carriage is thus freed from the variable escapement and goes back to its rest position under the action of its return springs, as described in some of the Vabove-mentioned copending applications. When it reaches its starting position the film carriage operates the contact RT. This disconnects the battery from the clutch and the lm carriage reengages with the variable escapement. On the other hand the battery which was applied to the winding of stepping switch FLR is withdrawn by the operation of contacts RT, so FLR moves into position 1 where its winding is connected by its level A to the source of impulses G, and it starts rotating. By closing its make contact, RT has connected the variable escapement motor magnet EV to the battery through control cam Ca6 and has energized stop pin of the variable escapement. The film carriage, which has under the effect of its inertia gone farther than its actual starting position, starts advancing step by step until its operating circuit is interrupted by cam Mp which opens the circuit when it reaches its true starting position. The sequence switch FLR maintains SE operated for some time and sends to the film feed device a number of impulses controlling the spacing between lines. The number of impulses is selected by a manual key FFK which selects a given level of FLR, each of these levels sending a different number of impulses.

Justification. between characters If the operator wants to justify between characters in the case of short lines when there is but one or no interword he actuates a special space bar between the character actuations, which registers the code combination 3 5- 6. n this ease the potential is directed by a lead |32 to the upper level of SZ in which the terminals are connected to the stop pins of the variable escapement. By this means, spaces of 0, l, 2, 3 or any number of units may be introduced between characters. For example, suppose that the words film carriage are to be written in a line of l1() units length. The widths of the characters plus the normal interwood space is 97 units. The number of justifying spaces is 11 (including the space between words). This procedure operates automatically to introduce an additional unit between successive letters (and in the interword space which is increased to 5) up to the last two letters. 2 additional units are inserted between a and g and between ug and nel Control of non-justified Zines If the operator does not want to justify a line he throws key NJK before operating key 22. This operates relay NJ and locks it on level B of FLR. The relay NJ therefore remains operated for the duration oi both the justification computation and the photography, and a little longer as in the case of relay SE, In position 2 of FLK, relay NJ connects immediately a battery to FLK so that it does not stop on this position and sends but one impulse to CI. In position 3 of FLK relay NJ opens leads |06, |08 and thus prevents PR from being operated. Only CI is operated in this position (through |04) and it goes back to its rest position. FLK goes over positions 4 and 5 aspreviously described. SZ has received but one impulse and is therefore on position 1 and its brush is connected to stop pin 4 of the variable escapement. All the interwords are thus given the normal minimum spacing of 4 units.

Line erasure If the operator wants to erase a line he operates key KLK (kill-line key) which operates and locks relays NJ and KL. The justification computation does not take place as explained above and relay CR is prevented from operating by a break contact of KL, which removes potential from lead |34. A transfer contact of relay KL supplies a potential to that part of lead |20 which runs to contact w of the translating circuit for the end of line signal. A break contact of CR at rest makes the flash circuit inoperative by a lead |36 which short-circuits the decoder. When the end of line signal is found in the register it is applied directly to FLR by a make contact of KL. The film feed circuit is made inoperative by a break contact of KL connected by a lead |38 between FFK and a break contact of KL. FLR makes a complete revolution and keeps SE operated long enough to erase the line completely.

By providing a transfer contact on relay NJ it is possible to select two different levels of FLR 'a common resistance r6 by a lead ist.

17 JL for'. theiilm -feed (or leading) whenthe. line is not justified.

Indicatmy devices Since the text as it appears 'on' the typewriter cannot give any useful accurate indication of the actual length of;A the linemeans are* provided l to give to the operatorsuilicient information to resistances rl, r2r3, r4 and 15 (Fig. 7 and this parallel combination is *connected inseries with v Each of theseresistances is' chosen so as to send into .the common resistor r6 a current of' a number of `milliamperes :corresponding'to its rank in the rbinary system. `lorinstan'ce with a battery of 24volts resistance rl .may "have the value of V24,000 ohms with a currentof'l'milliamp., re-

sistance r2, 12,000 ohms, resistance i3 '6,000, resistance r4. 3,000 and resistancer' 1500 ohms. Similarly when switch ACS reaches the justication .zone it adds in parallel resistances having Ythel following value: at one` step from. the end' of line f a resistance. r1 of 750 ohms, at two steps .a resistance. 18 of 375 ohms, r9 ofi25'0 ohms and T of 187.5 ohms. YThe current flowing through .resistance f6, whichhas a low value .of say 10 ohms, is therefore proportional tothe number vof unoperated `stages in the ccunter,v i. e. to thev line deficit. In the casewhen, on account of a correction, switch ACS has 4moved one step too much, and the subtraction switch SUS has also moved one step, the resistances connected. by ACS would. g'ive a current which Wasi too small.

. For correcting this source Nof error switch SUS adds in the circuit. resistances H I, H2, H3 vand 1"| Il` having respectively the values-of 750,375,

`250 and 187.5 ohms. vWhen .however switch .ACS

reaches, and passes, the endofY line position .f the resi'stances connected. into .thecircuit by SUS would be thecauseof erroneous readings. .Ac-

cordingly ACS introduces. aseccndsseriesof vresistances r|.5.,.11|`6,.rl'LHB .and H9 .of respectively a secondlowresistance T20, also. of,..1.0f.ohms. The .potential l.between the terminals.. of resistances ri .and 1:20 .is therefore trulyproportionalto .the value .of the .l-ine .deficit D, even if. .severalv .correctionshavebeen made.v Voltmeter V gives .thereforea reading which may be. calihratedin Width .uIl1tS.

.The Ijustification Uincrement D/N is given by a milliameter. -AM connected. across the same points. but. in its circuit a levelof switch CI inserts. in` lseries resistances proportional l to the number` offinterwords as show-neat4 the top oflig. 8. -Thusrthe operator is notied'w-hen the justificationrange `is reached, .and what .the

interword increment-would 'bek `if he stops typing .sensitive filmV F- and `a yflash tube L. The disk rotates continuously `and `the characters are -photographed .-by `Vsending an electrical-impulse lin ythe discharge tubeivhich illuminates for-.amex- 4potential given by the battery |45.

. across the inductance.

A18 ceedingly short length of time, afew microseconds. In spite of the ,great linear speed of the characters sharp pictures are obtained. In order to have an -accurate positioning of the characters on the film it is necessary to time the instant of the flash with an extreme precision. This result .is achieved by means of a -photoelectric impulse generated by a slitF associated with each char-v acter. Since it is possible to position on the disk the slit corresponding to a given character with absolute precision, for instance by photographing them simultaneously, the precision does not depend on the relative position of the characters lout only of the relative positions of each character and its associated slit. The photoelectric impulse is obtained by a nlm reader P (of the type used in sound movie projectors) which projects a thin luminous slit on the path of the transparent slits, and a photocell PH. The positioning photoelectric impulsesv are inoperative until they are allowed to prime the flash tube by means of a decoder of the type described in our copending application Ser. No. 770,320.

The decoder generates, at the moment when the character passes inphotographic position a relatively wide impulse which acts on an velectronic gate tube which lets the impulse go through. lThe photoimpulses from photocell' PH are amplified by a pentode tube Hifiv and appear as positive impulses in the anode circuit. They are applied to the control electrode of a gate tube' |45, also a pentode-with an appropriate bias This tube |46: is normally non-conductive since its screen grid is connected to the ground by a resistance Ml. On the other hand the decoder circuit comprises an inductance |48 and a battery |49. As long as the decoder circuit is closed a small vcurrent of a few milliamperes, flows in this cir-A cuit limited by a resistance |50. `When the brushes of the decoder findthe combination corresponding to that of the character thecircuit is operi as explained in the above-mentioned application and an induced voltage appears The amplitude andv form of this voltage depend. on the resonant circuit formed by the inductance |48 and a condenser |5|. This induced voltage, of positive polarity,

'is applied to the screen grid of tube |45 and makes it conductive during the -passage of the character .in photographing position. At the 1 exact instance at which the character is in the correct `position the photoelectric impulse .taires place and is transmitted to an amplifier tube |52 which reverses, its polarity and also limits its amplitude. The resulting positive impulse is sent to a trigger tube |53 (preferably of the @A5 type) and allows a condenser |54 to discharge into the induction coil |55. This discharge generates an impulse of several thousand volts which triggers the flash tube L and causes condenser |43 to discharge into this tube.

In .order to prevent the fish tube from .operating morethan once for every revolution condensers |43 and |4 are disconnected from the sourceof potential in. the beginning. of the active cycle of the decoder by a cam C053. These condensers charge through appropriate resistances during the following cycle devoted to the displacement of thei-llm carriage.

Timingl control The photography of one character comprises two cycles, -first aphotographic cycle during which .the characteris photographed and a step- 'i9 ping cycle during which the nlm carriage is displaced. The cams controlling these operations are shown in Figure 1l and are driven by the same shaft as the master character disk. The disk bears the characters on half of its periphery. The two successive cycles take place during a single revolution of the disk. There are ten cams. Cam Cai controls the return of the carriage to its starting position. Cam Ca2 operates the contacts of the impulse generator G used in the justification computation as previously described. Cam Ca3 short circuits the decoder during the stepping cycle and prevents any flash from taking place. Cam Cali charges the condenser I43 of the discharge tube and prevents the occurrence of more than one ilash per revolution, as described above. Cam Ca controls the operation of the selective stop members of the variable escapement. Cam Ca controls the operation of the variable escapement motor magnet EV. Cam Cal is the start cam which initiates the printing operation by closing the locking circuit of CR and SE relays at the proper instant. Cam Cali controls the sensing carriage EXP and Cain Cafe the sensing springs PLP as previously described. Cam Call] controls the locking circuit 42d for the relays TI to T1, so that the sensing contacts of the register may be freed as soon as they have operated the T relays.

Changing fonts Several fonts of matrices may be accommodated on the same disk, for instance roman on one half and italics on the other half. As stated above, the photography occurs during the first result is that the photographic cycle takes the place of the stepping cycle and vice versa.

Relay ACF is controlled by the register. When the sensing contacts iind pins 3--5 (which is the change-of-font signal) operated, a potential is applied through relays T3- T6 to relay ACF and relay BCF, Fig. 9. Relays ACF and BCF and the associated resistances rc and rd together form a flip-flop circuit by the change-of-font signal. Simultaneously the control potential is applied to stop pin zero to prevent any possible operation of the variable escapement. When the control voltage is removed, the flipflop assumes its second position, and remains there until signal 3-6 again appears in the register, whereupon the original font is restored.

While the preferred embodiment of the invention has been shown and described, it will be understood that it may be varied in many particulars, and that the invention is not limted to said embodiment.

Having thus described the invention, We claim:

1. A binary counter comprising a member of stages of flip-flop circuits, yeach flip-flop circuit having a contact representing the zero or unit condition of a stage, a direct entry circuit leading into each stage, a carry-over circuit leading into each stage except the first, and dual relay means for each stage having connections with both the direct entry circuit and the carry-over circuit to operate the flip-nop of said stage,lsaid connections operating in opposition, whereby said stage is inoperative upon simultaneous occurrence of a direct entry to said stage and a carry-over from the preceding stage.

2. A binary counter comprising a number of stages of flip-flop circuits, each flip-flop circuit having a contact representing the zero or unit condition of a stage, a direct entry circuit leading into each stage, a carry-over circuit leading into each stage except the first, a direct entry relay winding for each stage connected to the direct entry circuit and having provision to operate said stage, and a carry-over relay winding for each stage connected to the carry-over circuit and having provision to operate said stage, said windings operating in opposition to prevent operation of said stage on simultaneous occurrence of a direct entry to said stage and a carry-over from the preceding stage.

3. A binary counter comprising a number of stages of flip-flop circuits, each iiip-flop circuit having a contact representing the zero or unit condition of a stage, a direct entry circuit leading into each stage, a carry-over circuit leading into each stage except the first, and a two-winding relay to operate each stage having one Winding connected to the direct entry circuit and the other winding connected to the carry-over circuit, said windings operating in magnetic opposition to prevent operation of the relay on simultaneous occurrence of a direct entry to said stage and a carry-over from the preceding stage.

4. A binary counter comprising a number of stages of nip-flop circuits, each flip-flop circuit having a contact representing the zero or unit condition of a stage, a direct-entry circuit leading into each stage, a carry-over circuit leading into each stage except the first, a direct entry relay for each stage connected to the direct entry circuit and having contacts to operate said stage, and a carry-over relay for each stage connected to the carry-over circuit and having contacts to operate said stage, said relays having contacts to prevent operation of the stage on simultaneous occurrence of a direct entry to said stage and a carry-over from the preceding stage.

5. A binary counter comprising a number of stages of ip-iiop circuits, each flip-flop circuit having an indicating contact representing the zero or unit condition of a stage, a direct entry circuit leading into each stage, a carry-over entry circuit leading into each stage except the rst, a carry-over exit circuit leading from each stage having connections through the indicating contact of said stage to produce a carry-over on a direct or carry-over entry to said stage if said contact is closed, and relay means for each stage connected with the direct entry circuit and carryover entry and exit circuits to operate said stage and to cause a carry-over, said relay means having provision to cause a carry-over and to prevent operation of said stage upon simultaneous occurrence of a direct entry to said stage and a carryover from the preceding stage.

6. A binary counter comprising a number of stages of iiip-cp circuits, each flip-flop circuit having an indicating contact represnting the zero or unit condition of a stage, a direct entry circuit leading into each stage, a carry-over entry circuit leading into each stage except the rst, a carry-over exit circuit leading from each stage having connections through the indicating contact of said stage to produce a carry-over on a direct or carry-over entry to said stage if said Contact is closed, and dual relay means for each A.afeeateiii 2l stage connected. lwith` the directrentrycircuit and the carry-over entry and-exiticircu'its vto operate thesaid stage-and to-cause a carry-over,=said con- -nections to the entry circuits operating inoppos-ition,whereby said stage is inoperative and a `carry-over is produced upon simultaneousoccurrence of adirect-entry to'said stage. anda carry.- over from. the .preceding stage.

7. A binary counter comprising anumber-'of stages of flip-flop circuits, each "nip-flop circuit `having an indicating contact representing the -zero or unit condition of a stagefa'direct entry circuit leading into each stage, a carry-over entry circuit-leading into each stage except thefr'st, Aacarry-over ex-it circuitfleading from each stage having connections through the indicating contact of said stage to produce a carry-over on a direct or carry-over 'entry to said stageV if `said .contact is closed, adirect entryl relay winding for each stage connected tc the direct entry circuit 1and having provision to operate said stage, a carry-over relay winding for each stage connected `to the carry-over entry circuit and having provision to operate said-stage, and contacts controlled `by saidwindings andi connected lto the carry-over exit circuit, said'windings operating in opposition to preventoperation of said stage and to produce a carry-over on vsimultaneous occurrenceof a `direct entry tolsaid stage and a carry-overA from the preceding stage.

8.\A binary counter comprising a number of stages of nip-flop circuits, each nip-flop circuit having an indicating contact representing .the 4zero orunit condition -of a stage, a direct entry Acircuit leading into eachA stage, a carry-over entry .circuit leading .into each vstage except the first, a carry-overexit circuit leading from each'stage having connections through the indicating con- .tact of. said stage to produce a carry-over on a vdirect `or carry-over entry. to saidl stage Aif said contact is closed, and a two-winding relay to oper- Iate each stage having one winding. connected to the direct entry. circuit, the other winding connected to the carry-.over entryA circuit, and .con-

tacts connectedfwith- `the carry-over'exit. circuit,

`.said windings operating in magneticoppositionto prevent operationof the` relay and :to produce. a :carry-over onv simultaneous occurrence of a direct -entry to said stage and a carry-over fromthe preceding stage.

`9. A binary counter comprising a number Lof stages of. flip-flop circuits, each"flip.flop lcircuit 'having an indicating contact representing the zero or unitcondition of. astage, a direct entry .circuit'ileading into each stage, a carry-foyer.kr entry :circuit leading into eachstageexcept'the first, a carry-over exit circuit leadingi'f'rom each stage `having connections throughV the indicating .con-V ,stage and to produce a carry-over on simultaneous occurrence ofa direct entry to said stage a-nd acarry-over from the preceding stage.

10. Photographic` composing apparatus cornprising a keyboard,a `number vof code elements Aoperated by the keys ofthe keyboard, the code aelements'being.zdividedzinto a width-selector group .2 for `representing :numerically the Widths of selected characters and 1a character-selector .group for representing particular characters as distinguished from othershaving the same width, a. register for storing information. corresponding ytoa line of characters and interword spaces having register elements corresponding to eachof the 1code elements for .each .character and space, a

line counter, connections between .the widthselector group of code .elements and the linel rcounterito. add thewidth valuesv of the line, a

photographic exposure device controlled by the register elements corresponding to both groups to fprojectl the characters successively upon a sheet,

an additional circuit for increasing the maximum number of distinguishable characters of a given width as fixed by vthe number of characterselector elements used to store each character. said circuit including connections from the' keyboard to combinations of the code elements representing unused width values, corresponding connections from the code elements to the line counter to add said given width, and connections controlled by the corresponding register elements to operate the photographic exposure device and variable escapement.

12. In apparatus for composing justied lines, a keyboard, a multi-stage line counter actuated .by the keyboard for accumulating the 'Width values of selected characters and interword spaces in a line, an interword counter for counting the number of interwords in the line, a deficit meter calibrated to display the differencebetween the accumulated Width values and the length ofA a justified line, and an increment meter calibrated to display the ratio of said diierence to the number of interwords,` said meters being connected in a circuit wherein the decit meter is connected in .parallel witha first series circuit rincluding the increment meter and a resistance variable by the interword counter in accordance to the number of -interwords in the line,.and said parallel-connected circuit is connected across a voltage .proportional to current flowing in a second'series circuit including a source of electrical potential and -a resistance network connected with the .stages or the line counter, saidresistance network .causing ya current in said second series circuit corresponding to the amount by which the number in the line counter is less than its capacity.

413. Apparatus according to claim 12 wherein said line counter comprises a number of binary stages, each stage having a series circuit includresistance network including a selected resistance ofY the switch in parallel with resistances connected to the stages of the line counter.

15, lnl apparatus for composing justified lines, a keyboard, a multi-stage binary line counter .actuated by the keyboard for accumulating the .width values lof selected characters and interword spaces inea line, subtraction means for the 'line counter, an -interword'counter `for counting the number of. -lnterwords in the lineya deficit meter calibrated to display the difference between the accumulated width values and the length of a justified line, and an increment meter calibrated to display the ratio of said difference to the number of interwords, said meters being connected in a circuit wherein the deficit meter is connected in parallel with a first series circuit including the increment meter and a resistance variable by the interword counter in accordance with the number of interwords in the line, and the terminals of the decit meter are connected across a voltage proportional to the line deficit, said voltage being derived from a series-parallel circuit including a source of electrical potential, resistances in the stages of the line counter, resistances in the steps of a rst stepping switch having means to step whenever the line counter exceeds its capacity, and resistances in the steps of a second stepping switch having correction means to step whenever a line counter subtraction causes a step of the first stepping switch to be erroneous.

16` Photographic composing apparatus comprising a keyboard, a register actuated by the keyboard and having means for storing characters, a line counter, connections between the keyboard and the counter for adding into the counter the width values of the characters, a first stepping switch having a carry-over circuit connected to the last stage of the counter to advance the switch whenever a .carry-over impulse from said stage indicates that the counter has exceeded its capacity, subtraction means for the counter, and means for effecting subtraction from the rst stepping switch without reversing the direction thereof, said means comprising an additional stepping switch having terminals connected with terminals on the lrst stepping switch and Contact means to change the effective terminal position of the rst stepping switch.

17. Photographic composing apparatus comprising a keyboard, a register having means for storing information corresponding to selected characters and spaces in a line including means for numerically representing width values, a

vmulti-stage binary line counter, connections between the keyboard and the counter for adding into the counter the width values of the characters, and correction means for the counter comprising a single inverting relay having contacts in each stage of the counter, energizing means for causing the relay to invert the counter by changing the condition of each stage through said contacts, means actuated by the register for adding into the counter the width value of the erroneous character while said counter is in the inverted condition, and energizing means for causing the relay to reinvert the counter by changing the condition of each stage through said contacts.

18. Photographic composing apparatus comprising a keyboard, a register having means for storing information corresponding to selected characters and spaces in a line including means for numerically representing width values, a multi-stage binary line counter, connections between the keyboard and the counter for adding into the counter the width values of the characters, a first stepping switch connected to the last stage of the counter to advance the switch whenever a carry-over impulse from said stage indij the condition of each stage through said contacts, means actuated by the register for adding into the counter the width value of the erroneous character while said counter is in the inverted condition, a second stepping switch for effecting subtraction from the rst stepping switch without reversing the direction thereof including a switch transferring any carry-over impulse from the last stage of the counter on the last-mentioned addition to the second stepping switch, whereby a step of the second stepping switch changes the effective terminal position of the first stepping switch, and energizing means for causing the relay to reinvert the counter by changing the condition of each stage through said contacts.

19. Apparatus according to claim 18 including a correction cycling switch having a number of levels connected to the first and second stepping switches, the register and the counter, said cycling switch being operable to perform the consecutive steps of inverting the counter, adding into the counter the width value of the erroneous character, and reinverting the counter.

20. Photographic composing apparatus comprising a keyboard, a register having means for storing information corresponding to selected characters and spaces in a line including means for numerically representing Width values, a photographic unit actuated by theregister to project selected characters upon a sheet, a variablemotion device operable by the register for causing relative displacement of character projections on the sheet, a zone switch for controlling operation of the variable-motion device having a number of terminals representing increment sides,-

said switch having two levels, a contact on one level for introducing increments of space between interwords only, and a contact on the other level for introducing increments between characters.

21. Photographic composing apparatus comprising a keyboard, a register having means for storing coded information corresponding to the characters and sensing means adapted to sense the stored characters consecutively, a character carrier upon which the characters are disposed, means for causing movement of the characters through a projection position, projection apparatus for projecting selected characters upon a sheet, a variable-motion device for causing relative displacement of character projections on the sheet, a plurality of relays actuated by the register sensing means, holding means for said relays to hold their contacts for a predetermined time after each actuation by the register sensing means, said time being not less than the time necessary for all selectable characters to pass the projection position, and connections from said relay contacts to control the operation of the photographic unit and variable-motion device according to the characters stored in the register, whereby the sensing means moves to a position to sense the next succeeding character in the register before said projection and displacement is completed for the character preceding it.

22. Photographic composing apparatus comprising a keyboard, a register having means for storing coded information corresponding to the characters and sensing means adapted to sense the stored characters consecutively, means for photographing images of the characters upon a sheet, a variable-motion device for causing relative displacement of the character images on the sheet, a plurality of relays actuated by the 

